Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0079731 (B-cell lymphoma)
 16,671 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous studies suggest that heavy chain isotype switch (S) recombination is directed by cytokine-induced transcription of the unrearranged CH gene before recombination. In studies aimed at identifying other signaling pathways that promote switching, we discovered that inhibitors of the nuclear enzyme poly(ADP-ribose) polymerase (PARP) increase LPS-induced switching to IgA in the B cell lymphoma 1.29 mu and to IgG1 in LPS + IL-4-treated splenic B cells. PARP, which binds to and is activated by DNA strand breaks, catalyzes the removal of ADP-ribose from NAD+ and poly(ADP-ribosylation) of chromatin-associated acceptor proteins. This enzyme is believed to function in cellular processes involving DNA strand breaks as well as in modulating chromatin structure. In 1.29 mu cells, PARP inhibitors increase IgA switching by day 2 and cause a fivefold increase in switching on day 3 as assayed by immunofluorescence microscopy. In spleen B cells, the PARP inhibitor nicotinamide increases IgG1 switching by about twofold. Nicotinamide also causes a reduced intensity of hybridization of C mu- and C alpha-specific probes to genomic DNA fragments containing the expressed VDJ-C mu and the unrearranged S alpha-C alpha segments, respectively, in 1.29 mu cells, indicating that PARP inhibition increases rearrangement of these fragments. Induction of switching by PARP inhibitors is not mimicked by treatment with cAMP analogues or reduced by inhibitors of protein kinase A. Induction of switching by PARP inhibitors does not appear to involve increased levels of transcription of the unrearranged C alpha gene.
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PMID:Inhibitors of poly(ADP-ribose) polymerase increase antibody class switching. 825 3

The MHC class II I-A(s) positive B cell lymphomas reticulum cell sarcoma (RCS) that arise in > 90% of SJL mice by the age of 12 months have superantigen-like stimulating properties. In the present study, therefore, RCS cell lines were examined for abnormal expression of endogenous mouse mammary tumor virus (MMTV) proviruses. Extraordinarily high expression of a 1.8 kb mRNA hybridizing with the long terminal repeat (LTR) of MMTV was found in both primary lymphomas and in vitro RCS lines, but not in an SJL B cell lymphoma, NJ101, that does not stimulate syngeneic T cells, or in LPS activated SJL B cells. A cDNA was cloned from cRCS-2 and sequenced. A 31mer oligonucleotide probe, prepared based on the unique C-terminal sequence of this RCS-Mtv LTR, detected the 1.8 kb mRNA in all RCS lymphomas, while a similar probe for the C-terminal sequence of Mtv-8 LTR hybridized with the larger mRNA present in normal B cells and in NJ101. Preincubation with 19mer antisense S-oligonucleotides, prepared based on the sequences of the first two potential translation initiation sites common to both Mtv-8 and the RCS-Mtv LTR, significantly reduced the ability of RCS cells to stimulate syngeneic T cells. Moreover, transfection of NJ101 cells with the cloned RCS-MMTV cDNA conferred V beta 16 T cell stimulating properties on to these cells. It is concluded that expression of the product of this MMTV-LTR mRNA provides RCS with the strong T cell stimulating properties that it needs for its growth. These results thus identify a novel oncogenic property of MMTV-LTR.
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PMID:Linkage of superantigen-like stimulation of syngeneic T cells in a mouse model of follicular center B cell lymphoma to transcription of endogenous mammary tumor virus. 838 94

IL-12 is a heterodimeric cytokine composed of two covalently linked chains, p40 and p35. p40 expression appears to be restricted to monocytes/macrophages and B cells and is highly regulated, while p35 is more ubiquitously and constitutively expressed. To investigate the mechanism involved in the regulation of IL-12 expression, we molecularly cloned and characterized the murine p40 and p35 genes. The p40 gene spans over 14 kb, consists of eight exons and seven introns, and was shown to be localized on chromosome 11A5-B2 by fluorescence in situ hybridization. A single major transcription initiation site was detected by primer extension analysis, and a TATA box was found at approximately 30 bp upstream from the transcription initiation site. The 5' flanking region preceding the transcription initiation site induced the enhanced expression of a promoterless reporter gene after LPS stimulation when transfected into a macrophage-like cell line. In contrast, the p35 gene spans over 8 kb and consists of seven exons and six introns on chromosome 6C, and multiple transcription initiation sites were detected. The 5' flanking region lacks canonical TATA and CAAT boxes at the appropriate position, but, instead, contains GC-rich sequences and constitutively mediated promoter activity when placed upstream of a promoterless reporter gene and transfected into a B cell lymphoma cell line. Thus, the characteristics of promoter regions of p40 and p35 genes are quite different, and this would account for the different regulations of p40 and p35 expression.
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PMID:Molecular cloning and characterization of murine IL-12 genes. 855 82

The results of cytogenetic studies are reported in 76 patients with B-chronic lymphoproliferative disorders (B-CLPD): 60 patients with chronic lymphocytic leukemia (CLL), six with follicular lymphoma in leukemic phase (FLLP), five with splenic B-cell lymphoma with villous lymphocytes (SLVL), two with chronic prolymphocytic leukemia (CPL), two with hairy cell leukemia (HCL), and one with plasma cell leukemia (PCL). PHA (phytohemagglutinin), PWM (pokeweed mitogen), LPS (lipopolysaccharide from Escherichia Coli), TPA (phorbol 12-myristate acetate), IL6 (interleukin 6), and DxS (dextran sulfate) were used as mitogens. Mitoses were obtained in 75 cases. Clonal aberrations could be demonstrated in 34 cases (44%). In CLL, classical type, chromosomes 6, 11, and 13 were more frequently involved, whereas trisomy 12 was frequently found in CLL mixed-cell type, in FLLP, and CPL. In SLVL the deletion del(7)(q32) is noteworthy and miscellaneous chromosome abnormalities in the remaining patients were observed. Regarding the efficiency of mitogens, PHA turned to be the most effective in obtaining metaphases and in detecting clonal chromosomal aberrations.
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PMID:Cytogenetic studies in seventy-six cases of B-chronic lymphoproliferative disorders. 907 2

IL-12 is a heterodimer of two subunits, p35 and p40, encoded by separate genes that are regulated independently. To investigate the mechanisms underlying the regulation of the p35 gene, we characterized murine p35 expression in the B cell lymphoma line A20 and in bone marrow-derived dendritic cells. Multiple transcription start sites were identified in both cell types, resulting in four p35 mRNA isoforms (types I-IV) that differ in the number and position of upstream ATGs in their 5' untranslated regions. In nonstimulated cells, the predominant forms of p35 message (types II and IV) contained an additional upstream ATG, whose presence was shown to inhibit the downstream translation of the p35 subunit. After LPS stimulation, however, transcription initiated from alternate positions, so that the proportion of transcripts not containing this upstream ATG (types I and III) was significantly increased in the population of p35 mRNA. These type I and type III transcripts readily supported translation of the p35 subunit and its incorporation into bioactive IL-12. Furthermore, p35 mRNA levels were substantially up-regulated after LPS stimulation in both cell types. Thus, our results show that p35 gene expression is highly regulated by both transcriptional and translational mechanisms.
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PMID:Expression of murine IL-12 is regulated by translational control of the p35 subunit. 1020 30

Spontaneous germinal center (GC)-derived B cell lymphomas of SJL mice (RCS) transcribe a 1.8-kb Mtv-29 mRNA under control of the META-env promoter. The encoded vSAg29 stimulates syngeneic Vbeta16(+) CD4(+) T cells, thereby acquiring T cell help necessary for RCS growth. Other strains of B cell lymphoma-prone mice include Mtv29(+) C57L and MA/MyJ, and the Mtv29(-) Mtv7(+)-recombinant inbred strain, SW x J-1. The lymphomas of these mice produce similar mouse mtv-vSAg-encoding mRNA, as characterized by Northern blotting, PCR, and RNase protection. A 1.8-kb mRNA in C57L/J and MA/MyJ lymphomas hybridized with an Mtv29-specific oligonucleotide, whereas SW x J-1 lymphomas produced 1.8-kb transcripts hybridizing with an Mtv7-specific oligonucleotide. Similar META-env-initiated transcripts were absent from LPS-activated B cells from any strain examined but were detected in Peyer's patch RNA from SJL mice. Like typical SJL-derived RCS, all these lymphomas stimulated syngeneic CD4(+) T cells and Vbeta16(+) T hybridoma cells. Immunohistochemical staining of primary tumors showed the presence of peanut agglutinin binding (PNA(+)) highly mitotic lymphoblasts, suggesting their GC derivation. The findings indicate that this novel mRNA for Mtv29 is present in B cell lymphomas from several Mtv29(+) mouse strains. Additionally, this is the first description of the ability of Mtv7 to produce transcripts that are controlled and spliced identically to those of Mtv29 and that are expressed in SW x J-1, I-A(s+), lymphomas that also stimulate Vbeta16(+) T cells. Our results suggest an important role for mouse mtv-vSAgs and Vbeta16 T cell stimulation in the development of GC-derived murine B cell lymphomas.
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PMID:META-controlled env-initiated transcripts encoding superantigens of murine Mtv29 and Mtv7 and their possible role in B cell lymphomagenesis. 1131 79

Synthetic lipopeptides derived from the N-terminus of bacterial lipoprotein constitute potent immunoadjuvants for parenteral and mucosal immunization. When combined with tetanus toxoid (TT) or gliadin as antigens, the lipopeptide N-palmitoyl-S-[2,3-bis(palmitoyloxy)-(2RS)-propyl]-(R)-cysteinyl-seryl-(lysyl)(3)-lysine (P(3)CSK(4)) markedly enhanced the specific antibody levels. Lipopeptides also act as macrophage/monocyte activators: P(3)CSK(4) induced nitric oxide release from bone marrow-derived macrophages (BMDM) of LPS responder and nonresponder mice. The antitumoral effect of the lipopeptide was demonstrated by a strong cytostatic activity of the lipopeptide-treated macrophages against the murine B-cell lymphoma cell line Abelson 8-1. The chemically well-defined lipopeptides can be synthesized with high purity and reproducibility and constitute ideal agents to be combined with antigens/vaccines or antitumor treatment.
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PMID:Lipopeptide adjuvants in combination treatment. 1286 Jan 77

The modulation influence of Misgurnus anguillicaudatus polysaccharide on the expression of nitric oxide synthase (NOS), B cell lymphoma/leukemia-2 (Bcl-2, hepatocyte apoptosis inhibitor) and Bcl-2 associated X protein (Bax, hepatocyte apoptosis promoter) in mice's liver with immunological hepatic injury was studied. Immunological hepatic injury was induced by lipopolysaccharide (LPS ip, 0.2 mg kg(-1)) in bacillus calmette-guerin (BCG ip, 0.15 g kg(-1), once, before 7 days) primed mice. The mice were treated with M. anguillicaudatus polysaccharides (MAP) at doses of 30 mg kg(-1), 60 mg kg(-1), respectively, ig, once a day, and sacrificed on the 8th day after ip LPS for 4 h. In comparison to the normal mice, the nitric oxide production, serum alanine aminotransferase (sALT) and serum glutathione s-transferase (sGST) levels were increased significantly, iNOS and Bax expression were up-regulated by 16.5 times (P<0.001 vs. normal animal group) and 0.43 times (P<0.05, vs. normal animal group) respectively, cNOS expression was not apparently changed, and no Bcl-2 expression was found in immunological hepatic injury mice. The M. anguillicaudatus polysaccharide (30 mg kg(-1)) could reduce sALT, sGST and nitric oxide production levels (vs. BCG-LPS model control group) by 25.1%, 42.6% and 17.8% respectively, and the expression of iNOS and Bax was decreased (vs. BCG-LPS model control group) by 80.3% and 38.4%, while the expression of cNOS and Bcl-2 increased (vs. BCG-LPS model control group) by 58.7% and 352%, respectively.
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PMID:Protective effect of Misgurnus anguillicaudatus polysaccharide on immunological liver injury in mice. 1838 2

The hepatoprotective effects of acteoside from O. coerulescens were evaluated in BCG plus LPS-induced immunological liver injury (ILI) in mice. Acteoside (50, 150, or 300 mg/kg) was administered via gavage daily for 12 days. The liver index (liver weight/body weight), liver homogenate levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT), hepatic nitric oxide (NO), malondialdehyde (MDA) content, superoxide dismutase (SOD) activity, production of tumor necrosis factor-gamma (TNF-gamma) and interleukin-2, 4, 10 (IL-2, 4, 10), as well as histopathological changes of the liver were evaluated following the 12-day treatment. Moreover, the modulation influence of acteoside on the expression of B cell lymphoma/leukemia-2 (Bcl-2, hepatocyte apoptosis inhibitor) and Bcl-2 associated X protein (Bax, hepatocyte apoptosis promoter) in the mice liver with immunological hepatic injury was studied also. Acteoside (50, 150, or 300 mg/kg) effectively reduced the BCG/LPS-induced elevated liver index, liver homogenate AST and ALT levels, hepatic NO and MDA contents, restored hepatic SOD activity and reduced the degree of liver injury in ILI mice. The expression of Bax was decreased (vs. BCG + LPS model group), while the expression of Bcl-2 increased (vs. BCG + LPS model group). These results are close to those of DDB (as a reference drug), and suggest that acteoside has a protective and therapeutic effect on ILI mice, which might be associated with its antioxidant properties, immunoregulatory function and regulation of hepatic apoptosis.
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PMID:Protective effect of acteoside on immunological liver injury induced by Bacillus Calmette-Guerin plus lipopolysaccharide. 1954 87

Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling is one of the major pathways for cytokine signal transduction. However, the role of the JAK/STAT pathway in liver ischemia/reperfusion is not clear. This study focuses on Janus kinase-2 (JAK2), which functions upstream of signal transducer and activator of transcription 1 (STAT1) in JAK/STAT, and its role in the mechanism of liver ischemia/reperfusion injury (IRI). Partial warm ischemia was produced in the hepatic lobes of C57BL/6 mice for 90 minutes, and this was followed by 6 hours of reperfusion. Mice were treated with a JAK2 inhibitor (tyrphostin AG490; 40 mg/kg intraperitoneally) or vehicle 60 minutes prior to ischemic insult. JAK2 blockade resulted in a significant reduction of hepatocyte apoptosis and liver injury. Macrophage and neutrophil infiltration, as assessed by immunohistochemistry, was markedly decreased in AG490-treated livers in comparison with controls. The expression of pro-inflammatory cytokines [tumor necrosis factor alpha, interleukin 6 (IL-6), and IL-1beta] and chemokines [chemokine (C-X-C motif) ligand 10 (CXCL-10) and CXCL-2] was also significantly reduced in the AG490-treated group in comparison with controls. AG490-treated livers showed fewer cells positive for terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling and reduced cleaved caspase-3 protein expression in parallel with increased B-cell lymphoma extra large expression. We employed AG490 (75 mM) in primary bone marrow-derived macrophage (BMM) and hepatoma cell (CRL1830) cultures, which were both stimulated with lipopolysaccharide (LPS; 10 ng/mL). In BMM cultures, AG490 depressed otherwise LPS-induced pro-inflammatory gene expression programs (IL-6, IL-12p40, IL-1beta, CXCL-10, and inducible nitric oxide synthase). In hepatoma cells, AG490 reduced cleaved caspase-3 expression. Moreover, JAK2 blockade inhibited STAT1 and STAT3 phosphorylation. This is the first report documenting that JAK2 signaling is essential in the pathophysiology of liver IRI, as its selective blockage ameliorated the disease process and protected livers from inflammation and apoptosis.
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PMID:Blockade of Janus kinase-2 signaling ameliorates mouse liver damage due to ischemia and reperfusion. 2111 57


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